Engineering Pichia pastoris for improved NADH regeneration: A novel chassis strain for whole-cell catalysis

• Martina Geier,
• Christoph Brandner,
• Gernot A. Strohmeier,
• Mélanie Hall,
• Franz S. Hartner and
• Anton Glieder

Beilstein J. Org. Chem. 2015, 11, 1741–1748, doi:10.3762/bjoc.11.190

• utilization pathway of Pichia pastoris for improved NADH regeneration. By deleting the genes coding for dihydroxyacetone synthase isoform 1 and 2 (DAS1 and DAS2), NADH regeneration via methanol oxidation (dissimilation) was increased significantly. The resulting Δdas1 Δdas2 strain performed better in

• still maintaining a strong methanol flux towards oxidation to CO2 and NADH regeneration. Deleting only one isoform of the dihydroxyacetone synthase did not have such a severe impact on the methanol depending growth of P. pastoris. The growth rates were reduced by ~20% and by ~40% for the Δdas1 and Δdas2

• -out strains To evaluate the NADH regeneration potential of the generated knock-out strains, they were employed as hosts in whole-cell bioreductions based on the 2,3-butanediol dehydrogenase from S. cerevisiae YAL060W (BDH1). This enzyme was shown to specifically use NADH as cofactor, displaying high

An integrated photocatalytic/enzymatic system for the reduction of CO₂ to methanol in bioglycerol–water

• Michele Aresta,
• Angela Dibenedetto,
• Tomasz Baran,
• Antonella Angelini,
• Przemysław Łabuz and
• Wojciech Macyk

Beilstein J. Org. Chem. 2014, 10, 2556–2565, doi:10.3762/bjoc.10.267

• . For the approach discussed here, the production of one mol of CH3OH from CO2 requires three enzymes and the consumption of three mol of NADH. Regeneration of the cofactor NADH from NAD+ was achieved by using visible-light-active, heterogeneous, TiO2-based photocatalysts. The efficiency of the

• . Keywords: CO2 chemistry; electron transfer; enzymatic CO2 reduction; NADH regeneration; photochemistry; photosensitization; Introduction The reduction of CO2 to fuel is a technology that could contribute to the recycling of large quantities of carbon. Among the various routes, the enzymatic reduction of

• H2O splitting have received significant interest due to their potential environmental and resource preservation benefits [12][13]. Interestingly, the oxidized forms of some common waste organics may find practical application. The use of heterogeneous photocatalysts in the process of NADH regeneration

Biosynthesis of rare hexoses using microorganisms and related enzymes

• Zijie Li,
• Yahui Gao,
• Hideki Nakanishi,
• Xiaodong Gao and
• Li Cai

Beilstein J. Org. Chem. 2013, 9, 2434–2445, doi:10.3762/bjoc.9.281

• conversion potential [52]. The production yield could reach above 60% in the presence of glycerol [52] which may be responsible for NAD+/NADH regeneration. Large-scale preparation of L-tagatose has not been extensively studied yet due to elaborate routes or expensive starting materials. In our lab, the

• activity could be induced by L-arabinose [102]. Moreover, supplement of erythritol to the reaction mixture enhanced the conversion to L-sorbitol and one possible reason also lies in NADH regeneration resulting from erythritol dehydrogenation/oxidation. Conclusion The preparation and functional study of

• -talitol catalyzed by a halotolerant yeast strain Candida famata R28 could be significantly increased in the presence of various carbohydrates such as erythritol, D-sorbitol, ribitol and glycerol in the reaction mixture [100]. The faster consumption of the substrate could be explained by the in situ NADH